The invention relates to a mechanical fastening device for assembling or securing together two components, such as two molded cases containing electrical equipment and maintained in side by side relationship. The device includes a connection part or member which secures the coupled cases together in ratched or fastened position.
A known fastening device of this type comprises a connecting part inserted in a socket in one of the casings and ratched onto the coupled casing. This type of connection is suitable for the fixation of an auxiliary module or unit and the connecting part is mounted on the side face coupled to the adjacent module. The assembly of this auxiliary module by its opposite face requires the changing over of sides of the connecting parts. The mounting of these parts, which is held by a spring, is delicate so that the part can become detached and lost. The outline framework of an element fitted with these connecting parts is different to that of an element without, which complicates packaging.